Image caption
The public say they want monthly outlooks as well as forecasts for the coming week and fortnight

The Met Office needs new supercomputers to issue confident extreme weather warnings and more accurate long-term forecasts, a group of MPs has said.

A Science and Technology Committee report said that, despite improvements, the public still thought reliable seasonal predictions were not possible.

MPs want the Met Office to produce seasonal forecasts but be clearer about the chances of getting them wrong.

The Met Office said it was looking at ways to develop long-range forecasting.

Labour's Andrew Miller, the committee chairman, said it was "of great concern" that scientific advances were being held back by "insufficient computing capacity".

He said he recognised concerns about affordability, but a powerful new supercomputer could deliver "as much as a 10-to-one return on investment".

Last year, the committee heard from the Royal Meteorological Society that more supercomputers were needed to carry out complex calculations and the potential economic benefits of more accurate forecasts were "enormous" in terms of improved contingency planning for emergencies.

We need a little less tabloid sensationalism and a lot more information about probabilities,Andrew Miller, Commons Science and Technology Committee chairman

The MPs' report praised the Met Office's high standards of accuracy, but warned that media criticism of a "barbecue summer" prediction in 2009 had overshadowed the improvements it had made.

Mr Miller said: "The Met Office is consistently placed in the top three centres in the world for weather prediction, but accurate forecasts are of little use if they are not communicated well and understood by the public."

He suggested TV and radio weather forecasts use probable risk percentages, as they do in the US.

He added: "The media must be more responsible when it comes to long-range weather forecasting.

"We need a little less tabloid sensationalism and a lot more information about probabilities, so that the public can understand the odds of forecasts getting it wrong."

The report recommends the Met Office - which provides weather data to the government and the armed forces - work on a 10-year plan for supercomputing resources.

The body is largely funded by the government, with some additional money coming from the Civil Aviation Authority and other sources like the European Union.

The committee report insisted the government must set out its annual funding commitment for the next few years by the end of this financial year.

It also called on the business department to produce a business case on supercomputing by the end of summer.

The Met Office said no additional funding for supercomputers had been secured yet, but it was working with the business department on a business case.

It acknowledged better computers would improve the accuracy, reliability and relevance of forecasts on all timescales.

In the meantime, the Met Office said it was developing the science of long-range forecasts and ways to communicate it.

Currently, a long-range outlook appears on its website for contingency planners, but some members of the public have told the Met Office monthly outlooks would be helpful.

The Met Office has also experimented with probability forecasts, some of which are already being used in mobile phone services and on websites.